This invention relates to controlling the conditioning and delivery of air to a space or zone to be conditioned, such as a selected portion or zone of an office building.
The invention is particularly concerned with a subsystem which is part of a larger parent system, where the parent system provides cooled or chilled air to a plurality of subsystems which control the conditioning of adjacent zones on one building floor, for example. For such parent system, a central cooling coil and associated distribution system may supply the cooled air to the several zones of the office building floor, and a separate subsystem will then control the conditioning and distribution of the air to each of the respective zones. In the following specification, reference to a conditioned space refers to a space or zone which may consist of one or more individual rooms, and which is to be conditioned by one subsystem according to the invention. For both the parent system and the associated subsystems, the return air plenum is desirably the "attic space" between the under surface of the building floor structure and the ceiling of the floor space immediately below. References to "return plenum" in the following specification are intended to refer to such return air plenum.
The invention is concerned with a system and method for controlling the conditioning and delivery of air to a conditioned space in a manner which is most efficient from the standpoint of energy consumption. Energy waste is minimized by (1) eliminating any mixing of previously cooled air with previously heated air, (2) utilizing only the volume of precooled air which is necessary to maintain the desired space temperature, and (3) minimizing the use and size of air moving fans which require energy.
A principal object of this invention is to provide a system and method for controlling the temperature of air in a conditioned space, in a manner to minimize energy waste.
A more particular object of this invention is to provide a system and method for controlling the temperature of air in a conditioned space, without mixing the precooled air with warmer air prior to delivery to the conditioned space, thereby minimizing energy waste.
Another object of this invention is to provide an efficient system and method for controlling the conditioning and delivery of air to a conditioned space.
A further object of this invention is to provide an effective and efficient system and method for controlling the conditioning and delivery of air to various conditioned spaces or zones of a building, which spaces or zones have different conditioning demands.
Still another object of this invention is to provide a system and method for conditioning and delivering air to conditioned spaces of a building, which minimize the need for, and the utilization of, auxiliary air moving fans and thereby further minimize energy waste.
A system for accomplishing these objects includes a cool air duct for connection to a cool air supply duct, a warm air duct for communication with a return plenum, and a delivery duct connected to both the cool air and warm air ducts for delivering air to the conditioned space. A thermostat control device provides a varying control signal relating to the varying temperature of the air in the conditioned space. Damper means for the warm air allows air flow from the return plenum to the delivery duct and prevents reverse flow therein. A fan is disposed in the warm air duct for effecting air flow from the return plenum to the delivery duct. Variable flow control damper means is disposed in the cool air duct for varying the air flow therein between maximum and no flow conditions. A first actuator means is responsive to the thermostat signal for controlling the variable flow control damper means; and a second actuator means is responsive to the thermostat signal for controlling the damper means and the fan. The second actuator means is operative in one condition to start the fan simultaneously with the closing of the cold air duct damper means, and is operative in another condition to stop the fan simultaneously with the opening of the cold air duct damper means. In more detail a heating device is disposed in the delivery duct; and a third actuator means is responsive to the thermostat signal for controlling the heating device.